Although catalysts that include nickel-ligand complexes are used in many commercially and industrially important chemical processes, procedures for making those catalysts are not optimally efficient. Nickel metal atoms can be combined with phosphorus-containing ligands to generate hydrocyanation catalysts (see, e.g., U.S. Pat. Nos. 5,981,722, 7,629,484, and 7,470,805), but not always with optimal results. Nickel is poorly soluble, and many nickel metal preparations are unsuitable for use in catalysts. For example, when nickel metal is agglomerated, poorly reduced, or impurities are present, low levels of nickel combine with phosphorus-containing ligands and only small amounts of catalyst are formed. Moreover, nickel starting materials from different commercial sources can have different properties, and even when processed identically one source can provide nickel metal that can efficiently form complexes with phosphorus-containing ligands, while another source does not.
Nickel having better complex-forming properties is desirable, as are more efficient processes for making such nickel, so that greater percentages of nickel preparations can be used in nickel-ligand catalysts and so that less waste is generated during catalyst preparation.